MASignal.hpp

/*Copyright (c) 2007 by Ben Sunshine-Hill

Permission is hereby granted, free of charge, to any person or organization
obtaining a copy of the software and accompanying documentation covered by
this license (the "Software") to use, reproduce, display, distribute,
execute, and transmit the Software, and to prepare derivative works of the
Software, and to permit third-parties to whom the Software is furnished to
do so, all subject to the following:

The copyright notices in the Software and this entire statement, including
the above license grant, this restriction and the following disclaimer,
must be included in all copies of the Software, in whole or in part, and
all derivative works of the Software, unless such copies or derivative
works are solely in the form of machine-executable object code generated by
a source language processor.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.*/

#pragma once

#define MA_SLOT_CLASS \
  protected: \
  MAConnectionSet SignalConnections; \
  public:

#define MA_SIGNAL_CONNECT(_signal, _slot) \
  SignalConnections.Add(_signal->Register(*this, &_slot));

#define MAX_SIGNAL_ARGS 4

#include "3rdparty/FastDelegate.h"

#include <boost/noncopyable.hpp>
#include <boost/preprocessor/iteration.hpp>
#include <boost/preprocessor/repetition.hpp>
#include <boost/preprocessor/cat.hpp>
#include <boost/preprocessor/if.hpp>
#include <boost/preprocessor/comparison.hpp>
#include <boost/preprocessor/empty.hpp>
#include <boost/preprocessor/arithmetic.hpp>
#include <boost/preprocessor/logical.hpp>
#include <boost/preprocessor/comma_if.hpp>

#include <vector>
#include <utility>

template<typename T>
struct MASignalNode
{
  MASignalNode(T const& data, MASignalNode<T>* next) : next(next), refCount(0), data(data) { }
  MASignalNode<T>* next;
  // refCount is as follows:
  // n>0: Connection is still active, thanks to n holders
  // n<0: Event has been destroyed, but -n holders are left
  // n=0: Connection has been closed, but Event still exists
  int refCount;
  T data;
};

class MASignalNullType{};

class MAConnection
{
public:
  MAConnection() : m_node(0) { }
  template<typename DelegateType>
  explicit MAConnection(MASignalNode<DelegateType>* m_node) :
    m_node(reinterpret_cast<AnyNodeType*>(m_node))
  {
    if(m_node)
    {
      m_node->refCount++;
    }
  }

  MAConnection(MAConnection const& c) : m_node(c.m_node && c.m_node->refCount > 0 ? c.m_node : 0)
  {
    if(m_node)
    {
      m_node->refCount++;
    }
  }

  MAConnection& operator=(MAConnection const& c)
  {
    if(&c == this) return *this;

    if(m_node)
    {
      if(m_node->refCount > 0)
      {
        m_node->refCount--;
      }
      else if(m_node->refCount < 0)
      {
        m_node->refCount++;
        if(m_node->refCount == 0)
        {
          delete m_node;
        }
      }
    }

    m_node = c.m_node && c.m_node->refCount > 0 ? c.m_node : 0;
    if(m_node)
    {
      m_node->refCount++;
    }

    return *this;
  }

  ~MAConnection()
  {
    if(m_node)
    {
      if(m_node->refCount > 0)
      {
        m_node->refCount--;
      }
      else if(m_node->refCount < 0)
      {
        m_node->refCount++;
        if(m_node->refCount == 0)
        {
          delete m_node;
        }
      }
    }
  }

  bool Active() const
  {
    return m_node != nullptr && m_node->refCount > 0;
  }

  typedef MASignalNode<MASignalNullType> AnyNodeType;
  AnyNodeType* m_node;
};

class MAConnectionSet
{
public:
  void Add(MAConnection const& c)
  {
    m_connections.push_back(c);
  }

  void Clear()
  {
    m_connections.clear();
  }

private:
  typedef std::vector<MAConnection> ConnectionContainer;
  ConnectionContainer m_connections;
};

template<BOOST_PP_ENUM_PARAMS_WITH_A_DEFAULT(MAX_SIGNAL_ARGS, typename T, MASignalNullType)>
class MASignal;

class AutoTracked : private MAConnectionSet
{
private:
  template<BOOST_PP_ENUM_PARAMS(MAX_SIGNAL_ARGS, typename T)>
  friend class MASignal;
};


#define BOOST_PP_ITERATION_LIMITS (0, BOOST_PP_SUB(MAX_SIGNAL_ARGS,1))
#define BOOST_PP_FILENAME_1 "core/MASignalImpl.hpp"
#include BOOST_PP_ITERATE()
#undef BOOST_PP_ITERATION_LIMITS
#undef BOOST_PP_FILENAME_1
#undef nullptrTYPE_MACRO

namespace std
{
        template<>
        inline void swap<MAConnection>(MAConnection & left, MAConnection & right)
        {
                std::swap(left.m_node, right.m_node);
        }
}